Method for driving bolts into metallic bodies



United States Patent O METHOD FOR DRIVING BOLTS INTO METALLIC BDIES Otto H. Schmitz, Braunschweig, Germany, assignor to Walter Schulz, Wulfrath, Rhineland, Germany Application December 16, 1954, Serial No. 475,690

Claims priority, application Germany February 4, 1954 7 Claims. (Cl. 1-60) The present invention relates to the driving of bolts into metal, especially metal parts of considerable wall thickness, by means of powder power driving tools.

When driving bolts into metal, especially iron plates of considerable wall thickness, by means of powder power driving tools, that portion of the material which surrounds the driven-in bolt frequently bulges. These bulged portions not only impair the appearance but frequently also impair a proper fit of the parts to be connected by the driven-in bolt.

It has furthermore been observed that the iit of the bolt in the material is the less, the greater the 4bulging produced. Particularly in the so-called full material, i. e. the material which has a thickness equaling or thicker than the length of the bolt, the bolt fits especially poorly.

It is, therefore, an object of the present invention to provide a method and means which will overcome the above mentioned drawbacks.

. Itis another object of this invention to provide means whichl will prevent the material into which the b'oltis driven from bulging while simultaneously securing a proper tight t of the bolt in the material. i

These and other objects and advantages of the invention will appear more clearly from the following specication in connection with the accompanying drawings in which:

Fig. 1 illustrates a section through a metal part into which a bolt has been driven in the heretofore knol-'n manner.

' Fig. 2 illustrates a similar section through a metal part into which a bolt has been driven in conformity with the present invention.

Fig. 3 illustrates a one-piece disc for use in connection with the method according to the present invention.4

Fig. 4 is a split disc for use in connection with the present invention. Y

Fig. 5 shows an arrangement according to the present invention for use in connection with the driving of bolts into metal parts.

Fig. 6 shows a modied disc Vfor use in connection with the present invention.

Figs. 7 and 7a illustrate a top View and section respectively of a disc according to the present invention.

v General arrangement It has been found according to the present invention that the heretofore experienced bulging of the iron parts into which a bolt is driven by a powder power tool can be avoided by placing avmetal support for instance a metal disc on that portionv ofthe respective metal part into which the ,bolt is to be driven. The said metal support must be of a metal which is somewhat softer than the metal into which the bolt is to be driven. ."Supp'orts of duraluminfhave proved particularly advantageous in this connection., J.' 1

When driving bolts into wood or similar soft material, it is known to employ metal discs provided with a bore Patented Oct. 29, 1957 ICC therethrough and to place such discs upon the portion of the wood into which the bolt is to be driven in order to prevent the bolt from entering the wood beyond the desired extent. ln other words these metal discs oer the head or shoulder of the bolt sufficient resistance to limit the depth of penetration of said bolt. With this method, the support must be harder than the material into which the boit is to be driven in order to serve its desired purpose. When driving bolts into iron or other metal parts, such metal supports have heretofore not been employed because the employment of such metal supports or discs as they were used for preventing the penetration of a bolt into wood beyond the desired extent was considered senseless. The bolt which is driven into iron never enters into the iron beyond its shoulder or head because the iron material offers the shoulder too great a resistance to allow the shoulder or head of the bolt to enter the material. Surprisingly it has been found according to the present invention that the placing of such discs upon iron has the astounding effect that the bolt is considerably better anchored in the material while the heretofore encountered bulging of the iron part into which the bolt is driven is avoided. This phenomenon may be explained as follows:

When the bolt is entering the material, such volume of the iron part into which the bolt is driven has to be displaced as corresponds to the volume of the respective shaft of the bolt. if the metal support according to the invention is not employed, at the beginning of the penetration ofthe bolt into the material of the iron part, the material of the iron part is primarily displaced toward the outside, i. e. in a direction counter to the direction of driving of the bolt, because the material of the iron part does not encounter any resistance in its displacement toeffected by compression of the material of the iron part in the direction transverse to the axis of the bolt. Only at those portions at which this compression of the material occurs will the bolt tightly contact the material of the iron part so that the necessary adherence of the bolt to the iron part is obtained. However, the material which during the initial entering phase of the bolt into the iron part was displaced toward the outside cannot be reduced any more to any appreciable extent and thus forms the bulging portion below the head of the bolt. However, if in conformity with the present invention a metal disc is placed upon the portion into which the bolt is to be driven, said placing of said metal disc being effected prior to the driving of the bolt into the iron part, the bulging or displacing of the material of the iron part toward the outside during the initial driving-in phase of the bolt is prevented. This is due to the fact that the disc material is pressed under great force against the material of the iron part into which the bolt enters and thus offers a great resistance against any displacement of the material of the iron part toward the outside.

. creases with increasing bulging of the displaced material,

Tests conducted in an effort to pull the bolt out of the l aluminum alloy part into which it had been driven have proved that when employing the metal disc according to 0 the lpresent invention, the tight fit of the bolt in the aluminum alloy part is about from ve toten times greater than without the employment of the metal disc in con- This resistance in-` By selecting the` formity with the present invention; Thecomparative tests have, of course, been conducted under otherwise the same conditions, i. e. with the employment of the same type of bolts or Ystuds and with theV same typeand nia-gni; tude of the driving force. Preferably the method accorde' ing to the invention is carried out with a solid dis'cfiz'e.l a' disc hacing no hole therethrough. If a disc'wi-th hole is to be used, the holey has to have a diameter which is lessthan the outer diameter ofthe shaft Aofthe bolt so that the rim of the dise will tightly the bolt.

The suppoitt according to the'invention may' also beY formed of a split dise so that following the driving in' of therbolt into the metal part, the sections of the'disc support can easily be removed; If desired, the dise mayv be provided with one or more notches which will facilitate' avbrea'king of the disc. Y t U Y It hasfurthermore been found that the supporting disc also' serves as a guide for'the'rbo'lt and VthusY elfectiv'ely counters any tendency yof the bolt to bend; p'

l Y Y Structural arrangement n 'Referring nsw to the drawings in detail and Fig.- 1 thereof in particular, this figure Villustrates the heretofore known method according to which thev bolt 1 is--dri-'ven into the metal part 2 Without placing a metal support' of metal'd-isc uponv that portion of the metal part 2` into which the' bolt I is to be driven.Y Since thel material of the metal part can he displaced outwardly and thus form the bulgeV 4, the material does not tightly engage' the shaft arearv Siof the'bolt. e ThisV area of the shaftV isy therefore' ineffective in the anchoring of the bolt in the metal part.' The' zone of the metal part in which a compression of the material has Vbeen e'ec'ted is indicated in Fig. l by i= creased shading; Y e n e Fig.- 2 shows the same bolt' driven in'to thesame nntal pal-t 2 while employing'a support Vdisc pla'cd upon' the metlpaft 2 C'lfI'V'Iliy With the pself Vllf. Since the material oftl'le metal part 2 could not escape toward the outside, it has been compressed from the Vuppersurface ofY the metal part 2V downwardly into the material of the metal part as indicated by increased shading. It willl be evident Afrom the above, that in this waythe tight fitting `contact area fof' the shaftof Vthe bolt has been considerablyincreased and therefore .the bolt is considerably better anchored in the metal part 2.

Fig. 3 illustrates a support disc 6 for use in connection withV the present inventionV whioh disc is a solid disc and mayrconsist of duralumin.

Fig. 4'showsva support disc 'Gti likewise for luse in connectionwith the presentY invention, which disc consists of two sections 7 and 8, The split disc '6a isto be placed on kthe surface of the Vmetal part into whichthe bolt isrto be driven, in' such a manner that after the bolt has been driven into the metalV part, its axis is substantially coaxial Ywith the airis ofthe disc 6a so that lthe' cross isection of the shaft of the bolt will be located in the area 9 indicated byvdashed lines. This makes is ypossiblefollewi'ng the driving in of the bolt' 1 into the metal part' 2 easily trero've the 'disc sections from the vbolt and thermetal part 2. Y

Fig. illustrates a split support 'I3 likewise for use iii` connection with the present invention which makes it possible to drive Va plurality of bolts arrangedin prox-- imity to each other into the metal part 2.k Y d Y :The slupportdisc 10a shown inFig. 6 is provided with: notches at Vthe periphery of thedisc. Preferably atleast two notches are arranged se that they will be locatedYV dia-VY metrically opposite to each other. However, if desired more; than two notches may be provided. These notches willfacilitate ythe breaking up of the disc' in a plurality of patsafte'r the bolt -has'f'ben driven into the respective metalpart. t ..7 Figs'. 7 and-7u `show a further support disc 12 in. View and Yin section respectively. As will be seenfrom these contact the shaft of Y .two grooves.

'tigures,4 the disc 12 is provided with grooves 11 crossing part 2 into' which` the bolt is to be driven. To this end, vthe support may be fastened to the surface of the metal part 2 by means'of a non-hardening adhesive, or elanips'or similar devices may be mountedon the driving tool which will hold the disc in the desired position relative to theV barrel mouth of the driving tool so that when the driving tool is placed into driving position, the disc willpbe pressedk between the surface of the metal part Y2 and the' mouth ofthe barrel of the driving tool. lThe material of the discs must not be too thin or too soft because too thin or .too soft material of the discs will not ofer suth- Y cient resistance against the above referred to bulging. Tests have proved that the thickness of the discs may ad vantageously be selected` as about 0.7 times the diameterA of the shaft` of the bolt'. On the other hand, the discs must not be too thick and the material must not be too hard because otherwise the disc willoffer too greata Aresistance against the entering of the bolt into the metal part 2. This would mean a loss in energy of the bolt when penetrating the disc so that the bolt might not have sucientenergy left in order to penetrate into the metal Y part 2 up tothe shoulder andsuiciently, to compress the material surrounding the shaft ofthe bolt.

Tests cam'ed out with a disc material.,the vhardness .of whicheqtralled the hardness ofthe material of the metal 'part- 2` have proved that Vthe ldisc material bulged in the driving` direction kand was pressed into vthe vmaterial of the metal part 2. Inthis'way 'the contacting surface of: the bolt shaft with the adjacent material of the metal part 24 was decreased which inV turn decreased the adhesion of the boltY tothe metal part 2.'

It is, of course, evident from the above that the shape of the supporting disc is Vimmaterial and, therefore, Ydiscs of diterentshape, for instance, of square shape may beY employed. y-.1f a plurality of bolts are to be driven into: .the metal part with the bolts arranged adjacent each other for in?v stance along a line, a supporting disc or strip maybe employed which covers Van .area vextending overa length corresponding Yto the'row of bolts.. The Vemployment of such strip or disc has the advantage that, after driving the rst or the first two bolts into the metal part 21,. the support is fixed to the metal part 2 and no further'means are necessary to hold said strip ior discfor the driving of theV other bolts. Y

.It is, of course, understood' that 'the present invention is, by no means, limited to the particular arrangement" shown in ythe drawings but also :comprises any modifications within the scope of the appended claims..

What I claim is:

1. In the method et embedding a stud in an iron bodyV inwhich the stud lis @drivenby an explosive'lcharge into the iron body with one .end Vthereof embedded inl the iron*V body-and the other Aend thereof protruding `fron'rthe vironbod-y, the improvement -formore rmly yanchoring the stud in -the body kwhich .comprises driving the stud into the body .through an .aluminum alloy member maintained in surface engagement with .the body during the'driving of the stud therein.

Y 2. Improvement according Ito claim '1, infvv'ltieltsaidv 'Y aluminum alloy member has a thickness of lboltl? times the diameter-of the stud; Y Y l 1 Improvement @according 'to 2, in Vl'lvhich Mid aluminum alloy member a disc shaped member,

4. Improvement according to claim 3, in which said aluminum alloy member is a duralumin member.

5. Improvement according to claim 1, which includes removing said aluminum alloy member after the driving of said stud.

6. Improvement according to claim 1, in which said aluminum alloy member is a duralumin member.

7. Improvement according to ciaim 6, in which said aluminum alloy member is a disc shaped member.

References Cited in the le of this patent UNITED STATES PATENTS 169,734 Schalck Nov. 9, 1875 6 Gladding Nov. 5, 1889 Brigham Dec. 8, 1903 Pipes June 23, 1936 Temple Sept. 3, 1940 Hendrickson Jan. 12, 1943 Turechek July 10, 1945 Sopris Aug. 8, 1950 Meyers Nov. 27, 1951 Weingart Dec. 1, 1953 Bulmiller Ian. 24, 1956 

